Located at the interface between your body and its surrounding environment, your epidermis acts as a barrier against the entry of infectious agents and the loss of bodily fluids. At a microscopic level, the structures that provide the barrier function resemble bricks and mortar" with dead skin cells forming the bricks and lipids acting as the mortar. We investigated the role of the DNA binding protein KLF4 in directly regulating the process by which the epidermis establishes the barrier. Mice lacking KLF4 protein seem healthy at birth but die within 15 hours due to rapid water loss through their skin. To analyze the mechanism by which KLF4 regulates the development of barrier function we identified downstream targets of KLF4 genes which are turned on or off under the influence of KLF4. We identified these genes based on two complementary methods: cDNA microarrays and subtractive cloning. These targets encode proteins that regulate cell proliferation and major components of the cellular "bricks". Ongoing research assigns these transcripts to regulatory pathways based on their expression and function in the epidermis."